Junk Plant Millstone As A Indicator Of Problems with SRVs and PORVs Valves Nationwide

New inspection report 2016004

This is a representative report indicating problems throughout the Industry with safety relief valves and PORV valves. Poor maintenance on the PORV valve gave us TMI. These problems go across the plant employees, manufacturers and vendors since 2006. The new valves were way less reliable than the old ones.

How we get to Pilgrim today is through the replacement of their two stage safety relieve valves. The reliability of the old valves were horrible. They put in refurbished three stage SRVs through the nuclear junks yards in 2011. The new SRVs began leaking emediately upon startup. They had horrendous leaking problems with the new valves effecting capacity factor. In 2013, I made a complaint to the NRC saying the valves have a common mode issues and they are extremely unreliable. The NRC blew me off. In the 2015 Blizzard hard plant trip and LOOP, two valves failed to operate when needed. We got here because I professionally so embarrassed the NRC.

1) The commonality between Millstone(PWR)and(Pilgrim) is upon startup with new valves, they emediately began leaking. It takes them many failures and many years to confront the defective new valves.  

2) Generally the SRVs and PORVs are indicator components. It indicates the bureaucracies are dysfunctional.  

3) With new valves and leaking, the NRC should have emediately ordered the plant to shutdown and fix them. On the second leak, we will shut you down for a year. That's being tough!!!       
That is how you make everyone else behave in the industry.

·        Annual Sample:  Unit 2 ‘B’ Power Operated Relief Valve (PORV) Leakage

a. Inspection Scope

The inspectors performed an in-depth review of Dominion’s identification and correction

of conditions adverse to quality associated with repetitive leakage of Unit 2 PORVs since

modification and installation in 2006 during 2R17. 

The inspectors assessed Dominion’s problem identification threshold, causal analyses,

extent of condition reviews, compensatory actions, and the prioritization and timeliness

of Dominion’s corrective actions to determine whether Dominion was appropriately

identifying, characterizing, and correcting problems associated with this issue and

whether the planned or completed corrective actions were appropriate.  The inspectors

compared the actions taken to the requirements of Dominion’s CAP and 10 CFR 50,

Appendix B and assessed the effectiveness of the implemented corrective actions.  

b.  Findings and Observations

No findings were identified.  

In 2006, Dominion chose to upgrade the Unit 2 Pressurizer PORV and Operator

Assemblies to mitigate damage associated with repetitive installation and removal to

support off-site surveillance testing of the original plant equipment.  The new PORVs

were designed to require less maintenance and to be tested in place.  During each fuel

cycle since installation, either one or both of the new PORVs have leaked by their closed

valve seats.  This condition has resulted in Dominion isolating PORVs during each of the

last four fuel cycles.  On November 17, 2016, Dominion isolated the ‘A’ PORV due to

leakage as captured in CR1054065. 

The PORVs provide overpressure protection for the reactor coolant system (RCS) by

relieving pressure to the quench tank thereby protecting the RCS against brittle failure.

Additionally, the PORVs are sized to ensure that departure from nucleate boiling

specified acceptable fuel design limits are not exceeded during analyzed events.  The

rated capacity per valve is one half the capacity that prevents lifting the RCS safety

valves during normal plant operations and transients including a loss of load from full

power.  Furthermore, this capacity is sufficient to prevent lifting the safety valves in the

event of a continuous control rod withdrawal from low power, in conjunction with a

pressurizer pressure trip of the reactor.  Blocking or isolating a PORV will prevent the

valve from automatically opening on demand.

To correct PORV leakage Dominion has performed three recent ACEs with limited

success.  ACE 18846, from 2012, concluded that the incorrect subcomponents,

mismatched valve seats and discs, were used when maintenance technicians swapped

out a damaged seat during installation.  Dominion also identified lost bench and post-

maintenance testing opportunities in addition to training and procedural enhancements. 

In 2015, ACE 19950 found that Dominion failed to provide the vendor adequate testing

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requirements in the purchase order for the PORVs.  Dominion further identified that the

welded in configuration of the current PORV design does not allow for testing prior to

restoring the system.  ACE 1028983, in 2016, observed that Dominion failed to take

proper action upon identification of PORV leakage due to procedural weaknesses.

The Dominion CAP procedure, PI-AA-200, provides instructions to station management

to ensure selection of the most appropriate causal analysis tools during CR screening.

Consistent with previous screening, CR1054065 was screened as Significance Level 2,

Potentially Significant Condition.  These conditions are identified as precursors to

significant events.  PI-AA-200, Attachment 6, “CAQ Screening Matrix,” recommends

consideration of a root cause evaluation (RCE) for potentially significant repetitive

conditions. The inspectors observed that Dominion initially elected to perform another

ACE for isolation of the ‘A’ PORV captured in CR1054065.  However, consistent with a

healthy corrective action program, station staff assigned analysis of the issue identified

that the three recent ACEs had not successfully prevented PORV leakage and

requested elevation to a RCE to ensure the appropriate rigor.  Dominion has scheduled

completion of the associated RCE (CA3048134) for February 12, 2017.